Furnace truck



June 10; 1947. I J. M. LEE 2,421,894

FURNACE TRUCK Filed Sept. 4, 1944 2 Sheets-Sheet -1 www g June 10,1941

J. M. LEE

FURNACE TRUCK Filed Sept. 4, 1944 2. Sheets-Sheet 2 I Patented June 10, 1947 UNITED STATES PATENT OFFICE FURNACE TRUCK Jess Max Lee, Los Angeles, Calif.

Application September 4, 1944, Serial No. 552,649

17 Claims.

This invention relates to trucks which are typically used for the purpose of carrying metals during a heat treating operation. A short statement of the difiiculties attendant present known trucks will serve to make my invention more readily understood.

Furnace trucks are used for carrying material into and out of heat treating furnaces, and from the furnaces into quenching baths. The trucks are therefore subjected to the same high temperatures, and rapid temperature changes, as are the materials being treated. Body warpage and constant breakages of suchtru'cks have been commonly experienced, due generally to factors which will be noted.

A truck structure which is in more or less common use is made in skeleton form, an open framework structure. It is desirable that the trucks be as light as practicable in order to minimize the no-pay mass which must be heated each time a" braced. A floor for the frame work is provided 5 by securing a suitable metal mesh to the lower longitudinal and transverse frame members, continuous from end to end of the truck. The wheels are attached to the frame under the lower frame members and are usually in the simple form of wheels mounted on transverse axles so that they rotate and roll in longitudinal planes. In the ordinary construction, all of the longitudinal members and the flooring are continuous from end to end of the truck, and the transverse members and flooring are continuous fromside to side.

The frame members are commonly made of steel tubing or other steel shapes; and the material being treated is very commonly an alloy which has a coeflicientof expansion very different from that of steel. Long pieces of the material may extend the whole length of the truck. When the truck is in the furnace, and usually when it is in the quenching bath, its wheels rest either on the furnace floor, or rest on an elevator platform by which it is hoisted into the furnace and lowered into the bath. The coefficient of expansion of the truck frame, and the coefficient of expansion of the floor or elevator platform, eitherlikely to be different, or the frame and the floor or Flatform will be eiiectively heated to different temperatures in the furnace.

The reasons for the fast deterioration seem quite clearly to be somewhat as follows. We may suppose, for instance, that a steel frame truck is loaded with rather long lengths of an aluminum alloy. It is then rolled into the furnace and remains there until the material and the truck have reached a temperature equilibrium at a rather high temperature, say 1000" F. During the heating period, both the material comprising the load and the truck frame expand, but at different rates. Those differences in expansions inevitably result in the bending and buckling of the longitudinal truck members.

There is also usually a difference in expansion of the truck frame members and the floor or platform on which the truck rests. That difference may be due, as noted, either to different coeliicients of expansion or to different effective heatings of the truck and the member on which it rests. Unless the truck wheels take care of that differential in expansion, warping and buckling strains are again put on the truck frame. The usual simple wheel will not readily slide laterally on the support; and also, although the wheels are intended to roll easily in a longitudinal direction, it is difficult, unless some complicated bearing structure is used, to keep the wheels in good rolling condition when they are being alternately subjected to high temperature conditions and quenching conditions. The result in practice is that the wheels will not move readily in either the longitudinal or transverse direction; both the longitudinal and transverse truck frame members are subjected to bending and buckling from that cause.

The truck warpage which results from all of the fore-going causes has been found in experience to warp and buckle the trucks very badly within a relatively short period of use. And then, with repeated heat stressings, the truck frames very commonly fracture, the breaks commonly taking place at the points where the horizontal frame members join the vertical frame members, or at the points where the corner braces join the horizontal or vertical members.

'2 \J hinged or loosely joined or telescoping sections, and also including the use of swivel casters instead of simple wheels. But as far as is known none of those attempted solutions has been capable of solving the problems. Hinged joints between sections of the sectional truck, or equivalent loose joints, necessarily involve sliding and rubbing actions. And the same thing is true of swivel casters.

I have come to the conclusion after extended study of furnace trucks that, while a truck must be flexible to the extent necessary to absorb expansion and contraction differentials, at the same time to be successful it must not involve any surfaces which move in contact with each other in making the necessary adjustment to absorb the differential movements. It is consequently a general object of my invention to provide a framed truck structure which has good load-carrying rigidity and at the same time has sufficient fiexibility to adjust itself to, and absorb, the expansion and contraction differentials, but has no relative sliding and rubbing movements.

The truck designs which are illustrated in the accompanying drawings and described in the following detailed description are typical and illustrative of my invention. The framing of the truck may be described generally by saying that the truck asa whole is made up of a lower framing and an upper framing, in vertically spaced horizontal planes and interconnected by vertical posts. In one of the typical designs the upper and lower framings are constructed alike. In the other, the lower framing is the same while the upper framing is of somewhat modified structure to give a greater stiffness for carrying overhead-suspended loads. In all cases, the framings, and particularly the lower framings, have suflicient longitudinal and horizontal flexibility to accommodate the differential movements; and

I that flexibility, in the lower framings and in one case also in the upper framings, is reached by a structure made up of sections and subsections which are flexibly interconnected. For example, the lower framing as a whole is divided along transverse lines into a suitable number of main sections which are severally joined together by horizontally flexing connective structure which accommodates itself to and absorbs all differential longitudinal movements. And each of the main sections is subdivided, along a longitudinal line or lines into laterally related sub-sections which are also joined together by the same or a similar type of horizontally flexing connective structure which accommodates itself to and takes care of all differential transverse movements. Carrier wheels are placed under each of the sections. The flexible connective means is mainly flexible only in horizontal planes, so that the structure maintains good load carrying rigidity.

The invention will be better understood from the following detailed explanation of an illustrative and typical form of truck embodying the invention and shown in the accompanying drawings in which Fig. 1 is a perspective of a portion of a truck, showing one form of the structures which are typical of the whole truck,

Fig. 2 is a similar view showing another typical form of structure,

Fig. 2a is an enlarged fragmentary plan of a portion of the upper framing of Fig. 2; and

Figs. 3, 4 and 5 are fragmentary enlarged detail plans showing typical modifications of flexing connective structures.

In the form and design illustrated in Fig. 1, one typical intermediate main section of the truck is illustrated and is denoted generally by the numeral ID. This section is typical of all of the intermediate main sections of the truck, the number of sections being dependent upon the total truck length desired. The end main sections of the truck, such as designated by the numeral H in Fig. 1, are similar in structure to the typical medial sections, but are shorter, as will appear from the drawing and from what follows.

The upper and lower framing of each main section, in or II, is divided, along longitudinal lines, into transversely related half sections or sub-sections. Those two framing sub-sections are vertically interconnected by a vertical post or posts, with suitable bracings; and in the form of Fig. 1 the upper and lower framing subsections with their vertical interconnecting posts may be viewed as a subsection of the truck as a whole. A detailed description of a typical intermediate sub-section now follows.

Each truck sub-section has a lower outer longitudinal frame member 20, and an upper similar frame member 20a, joined together medially by the vertical post 2|. All these frame members are relatively rigid and may be made of any suitable steel shape, or a shape of other material. They are here shown as being composed of steel tubing, and the three members 20, 20a and 2| are preferably welded together. In its lower framing each sub-section has preferably a single central transverse rigid member 22, and in its upper framing a similar member 22a. The longitudinal and transverse horizontal members, and post 2|, are all welded together and are braced by corner braces 24, 25 and 24a, 25a. Thus, as here described in typical form, the lower and upper horizontal sub-section framings each are composed of a rigid braced T-shaped framing of which 29 may be viewed as the head and 22 as the stem. And the braced vertical post 2| vertically interconnects the upper and lower subsection framings by connections with them at the Tintersections.

The parts of the sub-section structure which have so far been described are intended to be relatively stiff, although it is not necessary that they be heavy enough to be absolutely unyielding. They are however not intended to flex to any substantial degree in accommodating the relative movements which have been spoken of, as other parts of each section are especially designed and intended to provide the flexibilities to take care of those relative movements.

As here shown, the remainder of the upper and lower sub-section framing is composed of flexible flat metal forming the ends and the inner longitudinal of each framing. Although the ends and longitudinal portions might be formed of separate pieces of flexible metal, it is preferred for simplicity to make all three of one continuous piece of metal, and they are so shown in the drawings. Thus one piece of flat bar steel is bent in plan to a general U-shape to form the lower framing ends 30 and the inner framing longitudinal 3|. The upper framing has similar members 30a and 3 a. The ends of the end members 3i! and Sila, are welded to the ends of outer longitudinals 2|] and 20a, and the middles of longitudinal members 3| and 3| a are welded to the inner ends of transverse tubular members 22 and 22a. As shown in the drawings, the flat which forms the members 30, 3| etc. has its longer cross secti0na1 dimension vertical; so that those :members may flex in a horizontal plane but are relatively rigid as to :flexure torsionally or .in vertical planes.

One carrier wheel .32 for each subssection is mounted on a :simple transverse axle 33 in brackets 34 attached to the lower :outer longitudinal 2:0 and to the *lrorizontal corner braces :24, the wheel being preferably located directly under :post 2|. The wheel may have either a simple bearing on its axle, or self-lubricating bearing sleeves, or packed :baill- .or roller-bearings may be provided. Each lowersub-ssection framing is ffloored with a panel of :metal mesh '35 which is c'o-extensive with that lower horizontal sub-section iramingand is secured, as by welding, to the several members which make up the lower rraming. These panels of metal mesh :do not extend between adjacent sub-sections or main sections, each being only coextensive with one .lower subsection framing. And the metal mesh, although sufiiciently strong to storm a. floor :on which small pieces :of material may rest, is sufficiently iflexiblc in .a horizontal plane not to interfere with the :flexings bfrmembers'iiil and-3! Each intermediate main section in is made up of two identical subsections and arranged .in lateral opposition to :each other as shown in .Fig. 1. .As the structures of these two sub-sections are identical, the same numerals have been applied to the' partsoi both.

It will be understood that the major part of the length of a long truck is usually made up of a suitable number :of main sections it, each composed of laterally related sub-"sections such as have been described. In Fig. 1 a fragmentary :part of the framing of the .nextmainintermediate section to has been shown, and it will be noted that its end menibers 3!! and 30a lie in spaced opposition to end members 311 and 30a :of the sub-sections which are fully shown and which have been described. The two :sets of inner longitudinals 3! and 3111,01 the two sub sections which comprise :a whole section, also lie in pairs in spaced parallel opposition, as shown in the drawings. And the other end members, 33 and 30!! (the ones shown at the left in Fig. 1) lie in spaced opposition to the similar end membersfieban'd 36c ofa special end section.

The special end main section, shown at the left-hand end :in is also composed of lorrgitudinally divided sub-sections. Each end subsection comprises lower and upper outer longitudinals 2th and Zilc, and vertical post 212) joins horizontals zoo and 260 by being welded to them at their terminal ends. Also the horizontal frame members 221) and 220 are welded to the terminal ends of 211b and 200, and a welded triangular brace structure is used in the corners composed or braces 124i) and 240 in horizontal planes and braces 251) and 250 in vertical planes. The wheels 32b for the end sub-sections are mounted on brackets secured to -24-12 and the lower horizontal braces, in a manner similar to that before described, but the wheels are here preferably located a little inward of the terminal ends of longitudina -ls b. The inner longitudinals 3lb and Bic are similar to the inner longitudinals 3| and (Ha. In all, it will be seen that an end section l i, and each of its half or sub-sections, are similar to the intermediate sec tions Ill except that the former are preferably shorter than the latter, and the vertical posts and the transverse members are located at the :end corners instead of in the .middles of the outer longitudinals. The pairs of inner longitudinals 6 31b and 1310 of the two sub-sections lie in paral lel spaced opposition in the same manner that the inner longitudinals 3i and 31a lie with relation :to each other.

From what has been said it will be understood that a truck of any desired length may be made up by assembling the suitable :number of sections l-B and/or H. Typically a long truck will have several intermediate sections ill and two end sections "M. .A short truck may have only one :or a (few intermediate sections; or a very short one may be composed of :just two end sections :1. Or, on the other hand, a truck may be composed entirely of sections l0 without any special end sections. In any such assemblage the opposed parallel relations of the horizontally flexible members 3i], 3!, etc. will be the same as :has been described; and the following "description or the interconnection of those flexible members .is typical.

The :interconnective or joining means between the several opposed pairs of flexible end members 30 etc. and inner longitudinals 3| etc. may be varied. It is only necessary that these spaced opposed pairs of members be locally joined to gether at limited zones or points, or at several connective points which are spaced apart from each :other; and that the connective points or zones be spaced away from the corners of the sub-.-framings. The ype of connection which is shown in Fig. 1 as illustrative .and suitable, is shown in fragmentary detail in Fig. 3. Each connection (designated :generally by the numeral 4t.) comprises ashort "piece of tubin or pipe 4! located between two opposed flexible members (30 for instance) actingas spacers between those two members and welded to each of the .members as indicated at 4 -2. Asshown in Fig. 1 there may be four such spacer connections 4!! between each of the pairs of longitudinals 3!, 3-1, and 31a. am.

From Fig. 1 it will be noted that these spacer connections are spaced longitudinally away from the transverse members 22 and 22a, and are also spaced longitudinally away from the flexible end members 39 and Sea. That arrangement provides for accommodating a relative transverse movement, of contraction or expansion, between the two sub-sections which form a main section H). The flexible members :3l and 34a may bend and flex in horizontal directions in their middle portions where transverse members 22 are located, and in their end portions where they join 'with transversely extending end members 30 and sea. The inner longitudinals 3lb and 3| 0 of the end section are similarly spaced and joined by similarly placed connective members 46b, as will be seen from Fig. -1.

Similarly, all of the opposed ,pairs of transversely extending end members 30 etc. are spaced apart and connected by connective members 4001. These connective members, shown as two in number in each instance, are in each case spaced inwardly "from the outside longitudinals vMl, 213a, etc, :and also spaced outwardly from the inner flexible longitudinals 31, 31a, etc. That placement allows all of the flexible members 30 etc. to flex horizontally in their portions adjacent both the outer longitudinals and the inner longitudinals; and that flexing allows the whole frame work to accommodate itself freely to all difierential longitudinal movements.

Thus, horizontal flexings in all directions are provided to accommodate all diiferential expansions and contractions; but at the same time the whole structure is relatively stiff and rigid as 7 regards flexings vertically, and the interconnections between sections and sub-sections involve no relative movements in themselves.

The exact form taken by the connective members 40 is of no great importance; it being their function of spacing and their described placements, which are important. Almost any localized connective formation, or connective block, will perform the desired functions. Thus, for instance, in Fig. 4 I show a short piece of flat bar Ma welded in place between two flexible end members 30. And in Fig. I show the connective block formed by locally bending the flexible end members 30I inwardly to meet each other and to be welded together as at 42 I.

In Fig. 2 I have shown a modified form of truck structure which is more particularly adapted for carrying loads suspended from its upper horizontal framing. In this modified form the lower framings of the several sections and sub-sections are the same as shown in Fig. l; as are also the vertical posts and braces. Those portions of the structure will be fully understood from the foregoing description of Fig. 1; and corresponding numerals, plus I00, are applied to all the corresponding parts.

In Fig. 2 the upper section and subsection framings are made so as to give greater strength against vertical fiexure, but at the same time to allow the flexibilities which are necessary to accommodate the flexings of thelower framings. Overall lateral and longitudinal expansion and contraction, to take care of the differentials which I have described, is necessary mainly in the lower horizontal framings; the upper horizontal framings need only to be so constructed as to allow the accommodation movements of the lower framings and to protect itself (the upper framing) and the interconnecting posts and bracings against damage and fracture. Thus, as shown in Fig. 2, the upper framing may be such as to have little or no lateral yielding qualities, but to have transverse members which extend continuously from side to side of the sections and which have, therefore, a relatively greater strength against vertical flexure.

As shown in Fig. 2, the upper framing of an intermediate section IIO has two side longitudinals I20a to which the posts I3I are connected and braced as in Fig. 1. Continuous transverse members I30a extend between the ends of longitudinals I20a to which they are welded. The central transverse members, corresponding to members 22a of Fig. 1, are made up of two parallel fiat bars I22a which are spaced by welded spacers Mile located, about as shown, in positions spaced from the center and from the outer ends of bars I22a. The outer ends of HIM do not join longitudinals I20a directly but are welded at their ends (see particularly Fig. 2a) to bridge bars I60 which have spaced feet IBI welded to IZta. The braces IZ Ia are welded to I20a and also to trans verse bars IZZa, preferably at points between the spaced spacers Mile. The transverse structure which is made up of the transverse bars I22a and the braces I2 ia forms a substantially non-yielding transverse connection between the two opposite longitudinals I20a; but the fact that the bridges I60 will yield in a transverse direction and that braces I24a are connected to I22a at points between spacers I40a, provides some transverse yield and a flexibility which protects the structure at the braced points from fracture by contraction and expansion.

Transverse members I 30a and I22a are central- 1y joined by welded longitudinals I3Ia arranged as shown and spaced by spacers I IIla.

The upper framing of the end section III is similar to that of end sections I I of Fig. 1 except that the two transverse members 30c of Fig. 1 are here formed as a single transverse bar I300 extending continuously between the opposite longitudinals I200; the central longitudinals I3Ic being welded at their ends to the through lateral Opposing laterals I30a of adjacent intermediate sections III] are spacedly joined by the spacers I401, as are also the opposed laterals I30a and I300 of adjacent end and intermediate sections. These spacers are laterally spaced from the centers of the several laterals and also from their ends; so that the whole upper framing has the same type of longitudinal yieldingness that the upper framing of Fig. 1 has.

The two typical structures of Figs. 1 and 2 have been described as including both a floor structure (the lower horizontal framings) and an upper structure (the upper horizontal framings) interconnected by the vertical posts. Such truck structures lend themselves well to carrying piled-up loads; the side posts confining the load laterally. However, if a fiat truck without side posts is desired, as it may be in many instances, the posts and upper structure may be omitted and the lower horizontal framing, only be used. Or a truck with a multiplicity of decks above the lower framing may be made simply by duplicating the upper framing at chosen levels.

The structures which I have described may be built to any desired dimensions, and to any desired relations of length, height or width. To give an idea of relative dimensions of the parts for a truck of an arbitrarily chosen size, I may mention certain typical parts, dimensions and materials for a truck of overall dimensions which is in common use in aircraft industries for heat treatment of aluminum alloys. Such a typical truck may have an overall length of 20 feet, an overall width of 36 inches, a frame height of approximately 38 inches, and may be made up of five intermediate sections each 38 inches in length overall, and two end sections of 25 inches overall lengths. The section frames of such a truck have been made up of steel tubing 1" O, D. with a 6" wall, and of flexible members made of A x 1 A" steel flat in the bottom framings and A x 1 flat in the top framings, The tubing of the lower horizontal frames, and for the corner post may be somewhat heavier than the other tubular frame partsfor instance, of 1 0. D. tubing. The material of th tubing may be that of the well known Shelby tubing, and the material of the flexible flats may be ordinary structural steel. Trucks of such dimensions, and constructed of such materials have now been in extended service and have been found to have ample load-carrying rigidity of structure, and at the same time to have such horizontal flexibilities that the trucks have proved themselves to have a useful life many times longer than furnace trucks which have been commonly in use in the part.

I claim:

1. A furnace truck structure, including a plurality of longitudinally spaced main sections, each main section composed of a plurality of transversely spaced sub-sections, means flexible transversely of said structure forming connections between the sub-sections of each main section, and means flexible longitudinally of said structure 9:, forming connections between the several main sections 2: A furnace truck structure as specified inclaim. 1, and in which: each main section: includes two sub-sections, each sub-section having a rigid outer longitudinal member, a rigid transverse member rigidly secured at its outer end to the outer longitudinal member and extending inwardly therefrom, an inner longitudinal memberflexible transversely of said structure and se cured tothe inner end of the transverse member, a transverse end member flexible longitudinally of said structur and secured at its outer end to an end of the outer longitudinal-member and secured at its inner end to the inner longitudinal member; means locally connecting the flexible inner longitudinal members of the twosuh-sections together in spaced parallel relation, said. connective means being spaced longitudinally from the transverse members. and from the end members, and means locally connecting the flexible end members of adjacent sections together in spaced. parallel. relation, said connective means being spaced laterally from both the outer and inner ends of the flexible end members.

3. A furnace truck structure as specified in claim 1, and in which each ofa plurality of main.

sections is composed of two complementary sub sections, each sub-section having a horizontal framing comprising an outer longitudinal member, a, transverse member rigidly secured at its outer end to the, middle] of said longitudinal member and extending inwardly therefrom, bothsaid members being relatively rigid, an inner longitudinal member flexible. transversely of said structure and secured at its middle to the inner end of the transverse member, transverse end members flexible longitudinally of said structure and rigidly secured at their outer ends to the ends of the outer longitudinal. member and at their inner ends to the ends of, the inner longitudinal member; means locally connecting the flexible inner longitudinal members of each pair of sub-sections together in spaced parallel relation, said connective means being spacedv longitudinally from the several transverse. members,

and means locally connecting the flexible endmembers of, adjacent sections together in spaced parallel relation, said connective means being.

spaced laterally from both. the outer and inner ends of the. flexible end members.

4. A. furnace truck structure as specified in claim 1 and in which each main section includes two sub-sections, each sub-section having a relatively rigid outer longitudinal member, a relatively rigid transverse member rigidly secured at its outer end to the outer longitudinal? member and extending inwardly therefrom, an inner longitudinal member flexible transversely of said structure and secured to the inner end of. the transverse member, a transverse end member flexible longitudinally of said structure and secured at its. outer end to an end of the outer longitudinal member and secured at its inner end to the inner longitudinal member; means locally connecting the flexible inner longitudinal members of the two sub-sections together in spaced parallel relation, said connective means being, spaced longitudinally from the transverse membersv and from the end members, and means 10- cally connecting theflexible. end members of ad jacent sections together in spaced. parallel relation,. said connective means being spaced laterally from the outer and inner ends of the flexible endmembers, said connective means between the scveralfiexible members being in itself rigid sd that no: relative movements are allowed between the interconnected flexible members at their pointsof connection.

5. A furnace truck structure as specified in claim 1,,andin which each'of a plurality of main sections iscomposed oftwo complementary subsections; each sub-section having a horizontal framingcomprising; an outer longitudinal member; a transverse member rigidly secured at its outer end to the middle of said longitudinal membar and extending: inwardly therefrom, both said members. being relatively rigid, an inner longitudinal member flexible: transversely of said structure and secured at its middle to the inner end of the transverse member, transverse end members flexible longitudinally of said structure and rigidly secured at their outer ends to the ends of the outer longitudinal member and at their inner endsrto the ends of the inner longitudinal mom-- ber; means locally connecting the flexible inner longitudinal membersof each pair of sub-sections together in spaced parallel relation, said connective means being. spaced longitudinally from the several transverse members, and means locally connecting: the flexible; end members of adjacent sections: together in spaced" parallel relation, said connective means being spaced laterally from both theouter and: inner ends of the flexible end members, said connective means-betweentheseveral. flexible members being in itself rigid so that no: relative movements are allowed between the interconnected flexible members at. their points of connection.

6. A. furnace truck structure as specified in claim 1:, and in which eachof a plurality of main: sections is composed of two complementary subsections; each sub-section. having a welde horizontlalv framing comprising a relatively rigid outer longitudinal member; a relatively rigid transverse member joinedv at one endto the longitudinal member,. an inner longitudinal and a. transverse end member formed of a, single bent length of fiat metalwith' its longer cross-sectional dimensionvertical. so-that the inner longitudinal memher is. flexible in a horizontal direction transversely of the structure and the transverse end member is flexibleina horizontal direction longitudinally of the. structure; welded spacer block-s locally interconnecting the. inner flexible longitudinal members, of each pair of sub-sections and similarly interconnecting the adjacent flexible end members of adjacent sections, the. spacer blocks being located at medial portions of the flexible members-away from their ends.

7-. A sub-section structure for a furnacertruck of the type described, said sub-section structure including a. horizontal framing having a. rigid outer longitudinal member, a. rigid transverse member rigidly secured at its. outer end to the outer longitudinal member and extending inwardly therefrom, a-laterally flexible inner longitudinal member secured rigidly to the inner end of. the transverse member, and a longitudinally flexible transverse-end-mcmber secured rigidly at its outer end to an end: of the outer longitudinal member and rigidly secured at its inner end to an end of the inner longitudinal member.

8- A sub-section structure as specified in claim 7, land inwhich the. rigid transverse member is joined tothe middle of the outer longitudinal member, in which there are two transverse flexible end members secured to the two ends-of the outer longitudinal member, and in which the end members and the inner longitudinal-member are 11 formed of a single bent length of metal flat with its longer cross-sectional dimension vertical.

9. A furnace truck structure as specified in claim 1, and in which each main section includes two sub-sections, each sub-section having upper and lower horizontal framings and each of said framings including a rigid outer longitudinal member, a rigid transverse member rigidly secured at its outer end to the outer longitudinal member and extending inwardly therefrom, an inner longitudinal member flexible transversely of said structure and secured to the inner end of the transverse member, a transverse end member flexible longitudinally of said structure and secured at its outer end to an end of the outer longitudinal member and secured at its inner end to the inner longitudinal member; a rigid vertical post secured to the two horizontal framings of each sub-section at the points of junction of the rigid longitudinal and transverse members; means locally connecting the flexible inner longitudinal members of the two sub-sections together in spaced parallel relation, said connective means being spaced longitudinally from the transverse members and from the end members, and means locally connecting the flexible end members of adjacent sections together in spaced parallel relation, said connective means being spaced laterally from both the outer and inner ends of the flexible end members.

10. A furnace truck as specified in claim 1, and in which each main section includes two subsections, each sub-section having upper and lower horizontal framings and each of said framings including a rigid outer longitudinal member, a rigid transverse member joined at one end to the longitudinal member, an inner longitudinal and a transverse end member formed of a single bent length of metal flat with its longer cross-sectional dimension vertical so that the inner longitudinal member is flexible in a horizontal direction transversely of the structure and the transverse end member is flexible in a horizontal direction longitudinally of the structure; a rigid vertical post secured to the two horizontal framings of each sub-section at the points of junction of the rigid longitudinal and transverse members; welded spacer blocks locally interconnecting the inner flexible longitudinal members of eachpair of sub-sections and similarly interconnecting the adjacent flexible end members of adjacent sections, the spacer blocks being located at medial portions of the flexible members away from their ends.

1 A sub-section structure for a furnace truck of the type described, said sub-section structure including upper and lower horizontal framings, each framing having a. rigid outer longitudinal member, a rigid transverse member rigidly secured at its outer end to the outer longitudinal member and extending inwardly therefrom, an inner longitudinal member flexible transversely of said structure and secured rigidly to the inner end of the transverse member, and a transverse end member flexible longitudinally of said structure and secured rigidly at its outer end to an end of the outer longitudinal member and rigidly secured at its inner end to an end of the inner longitudinal member; and a rigid vertical post extending between the two horizontal framings and rigidly joined to them at the points of juncture of their rigid longitudinal and transverse members.

12. A sub-section structure as specified in claim 11, and in which each of the horizontal framings includes a rigid transverse member which is joined to the middle of the outer longitudinal member, each said framing also including two transverse end members each flexible longitudinally of the structure and respectively secured to the two ends of the outer longitudinal member, and the two end members and the inner longitudinal member being formed of a single bent length of metal flat with its longer cross-sectional dimension vertical.

13. A furnace truck as specified in claim 1, and provided with a flooring comprising flexible individual floor panels co-extensive with each of the several sub-sections.

14. A sub-section structure as specified in claim '7, and provided with a flooring panel of flexible material limitedly co-extensive with the horizontal framing and secured thereto.

15. A furnace truck structure of the type described, said structure including a lower horizontal framing composed of a series of longitudinally spaced sections, each section composed of transversely related sub-sections, means forming connections between adjacent sections providing for yielding expansion and contraction of the series of sections longitudinally of the structure, means forming connections between the several transversely related sub-sections providing for yielding expansion and contraction of the transversely related sub-sections transversely of the structure, vertical posts mounted at their lower ends one on each sub-section, and an upper framing interconnecting the upper ends of the several posts, said upper framing being yieldingly expansive and contractive longitudinally of the structure.

16. A furnace truck structure of the type described, said structure including a lower horizontal framing composed of a series of longitudinally spaced sections, each section composed of transversely related sub-sections, means forming connections between adjacent sections providing for yielding expansion and contraction of the se ries of sections longitudinally of the structure, means forming connections between the several transversely related sub-sections providing for yielding expansion and contraction of the transversely related sub-sections transversely of the structure, vertical posts mounted at their lower ends one on each sub-section, and an upper framing interconnecting the upper ends of the several posts, said upper framing being yieldingly expansive and contractive both transversely and longitudinally of the structure.

17. A furnace truck structure of the type described, said structure including a lower horizontal framing composed of a series of longitudinally spaced sections, each section composed of transversely related sub-sections, means forming connections between adjacent sections providing for yielding expansion and contraction of the series of sections longitudinally of the structure, means forming connections between the several transversely related sub-sections providing for yielding expansion and contraction of the transversely related sub-sections transversely of the structure, vertical posts mounted at their lower ends one on each sub-section, and an upper framing interconnecting the upper ends of the several posts, said upper framing beingcomposed of a series of longitudinally spaced sections each of which is mounted on the upper ends of the posts which are related to one lower framing section,

7 said upper framing sections being substantially unyielding in a direction transverse of the structure, and yielding mean forming connections between adjacent sections providing for yielding expansion and contraction of the series of upper framing sections longitudinally of the structure.

J. LEE.

REFERENCES CITED The following references are of record in the file of this patent:

Number Feldtkeller Oct. 22, 1918 

